A wide variety of farinaceous (starch and protein-based) snack food products are presently available to the consumer. Many of these products are in the form of chips, strips, and extruded pieces. Some of these products are expanded or puffed and contain a cellular or honeycombed internal structure. Most of the present-day snack products contain a fairly high level of fat, either in the form of separately added ingredients, such as cheese, or in the form of fats absorbed by the product during frying, as in the case of corn or potato chips. While fat improves the flavor and palatability of these products, it also increases the caloric value of the product. Accordingly, it would be desirable to provide low fat snack products which have an attractive appearance, texture and taste.
There have been several attempts at lowering the fat content of potato chips and of potato snacks made from doughs. One method involved coating chips with an aqueous dispersion of a high amylose starch. This is said to produce a potato chip with minimal oil pick-up and low variation in the amount of oil absorbed. (see RE 27,531 of U.S. Pat. No. 3,597,227 issued to Muray, et al., 1971). Coating of breaded or batter food products with a film forming agent such as gelatin or starches is also said to lower oil absorption by the foods when they are fried (U.S. Pat. No. 4,511,583 issued to Olson, et al, 1985). An alternative coating of raw starchy foods was described in U.S. Pat. No. 4,058,631 (Roan, 1977) which involves coating the food surface with an aqueous solution of alpha amylase enzyme. This is said to lower the fat absorption of the product during frying.
Other ways to lower the oil content involve removing oil from fried products by steam treatment, coating a potato slice with oil and then finish cooking with microwave or steam or other heat. Frying potato slices until they are partially cooked and then drying them has also been tried. See for example the following patents:
U.S. Pat. No. 4,756,916 to Dreher et al (assigned Frito Lay, 1988) describes a process for making a low fat potato chip wherein washed potato slices are partially coated with oil, blanched at a temperature of 70.degree.-100.degree. C. and then baked to a temperature at least 200.degree. C. When the moisture content of the partially dried slices is reduced to 10-25%, the slices can be further baked at a lower temperature (145.degree.-160.degree. C.) to finish drying the slices to a moisture content of 2 weight percent. The product is said to have the texture, flavoring and color characteristics of a conventional fried chip.
U.S. Pat. No. 3,402,049 to Mancuso et al (assigned General Foods, 1968) describes a process for making potato chips having a total fat content of 20-30% by weight. Raw potato slices are soaked in an edible fat, drained to remove excess fat and then heated to elevated temperatures to surface fry and dehydrate the potato slices.
U.S. Pat. No. 4,283,425 to Yuan et al (General Foods, 1981) describes a potato chip having a fat content of up to 10%. This chip is prepared by coating raw potato slices with a globular protein, applying a layer of edible oil on top of the protein coating, and then subjecting the raw coated slices to microwave heating.
U.S. Pat. No. 4,721,625 to Lee et al (Borden, 1988) describes a process for preparing low fat potato chips in which peeled raw potato chips are fried in oil to a moisture content of 10-25% by weight. The partially fried potato slices are protected against oxidation, and the oil is removed from the surface. The chips are then dried to a moisture content of 1.5-3%. Superheated steam is used to remove the fat from the chips. The superheated steam can be used as a drying agent also.
Canadian Patent 1,151,945 issued to Mehta et al (General Foods, 1983) describes a potato chip having a low fat content which is prepared by microwave heating. Before microwave heating, the raw potato slices are coated with an edible oil sufficient to bring the fat content to 20%.
U.S. Pat. No. 4,537,786 issued to Bernard (Frito Lay, 1985) describes a process for manufacturing a low oil fried potato chip wherein the potato slices are fried in oil to a temperature of about 280.degree.-320.degree. F. (138.degree. C.-160.degree. C.), removed from the oil, and then contacted with an oil removing blast of hot air for from 1-10 minutes. This hot air removes the excess oil as well as finishes cooking the chip.
Canadian Patent 957,896 issued to Hai et al (General Foods, 1974) describes a process for decreasing the fat content of fried chip-type potato products. The fried food product is centrifuged at at least 352 G of force while being contacted with superheated steam or saturated steam. The heat and steam remove the fat and finish cooking the chips.
The above processes apply to whole potato slices and are not easily adapted to products made from doughs. In addition, the heating process herein is accomplished using molds. These molds serve two functions:
1. to hold and shape the product; and PA0 2. to transfer the heat into the product.
It is an object of this invention to make a shaped snack food with a lower fat content (between about 10% to about 25%) which has the texture and flavor of a fried snack by coating a dough piece with oil and then heating the dough piece to remove the moisture and to cook it.